I'm looking for some ballpark figures for sizing on EV 9 mail archiving. I have a client with around 3800 comprising of two main sites  - site A will have approx. 1800 users, site B about 1200 users and the balance of the users located in various smaller sites.

EV is currently installed in the environment at site A with site B being roughly 1000 miles away. I estimate that the company generates around 100000 - 150000 mails a day and users will frequently access archvied items although I cannot say at what rate that happens although from the calls received it is quite frequent.

What general sizing recommendations would anyone suggest for an environment such as this?